Duplex centrifugal separator



April 16, 1935. s. c. LINDBERG DUPLEX CENTRIFUGAL SEPARATOR Filed Mar 0h 7, 1930 JzwW: Jvm 625M557,

W Z v Patented Apr. 16,' 1935 I I UNITED STATES PATENT OFFICE DUPLEX CENTRIFUGAL SEPARATOR Sven C. Lindberg, New York, N. Y., asslgnor, by mesne assignments, to'Centrifugal Engineering and Patents Corporation, New York, N. Y., a corporation of New Jersey Application March '7, 1930, Serial No. 433,888

8 Claims. (01. 233-45) This invention'relates to improvements in cenmay be provided, but there is a practical limit trifugal separators by means of which a fluid can to such multiplication of drums, owing to the fact be separated from impurities of different specific that the drums must be spaced from one another, gravities. While applicable to centrifugal sepaand. if the difference between the diameter of the rators in general, the invention relates more speinnermost drum and that of the outermost drum 5 cifically to separators f r re ovi foreign tis too great, the difference between the centrifuter from aqueous suspensions of cellulosic mategal forces g in these drums y be 0 .rial such as wood pulp, ground wood, cotton lingreat Satisfactory p t o ters, bagasse, cornstalks, bamboo or other fibers. According to the Present invention a p a o 10 Centrifugal separators of this type ordinarily mechanism is provided n whic mu tiple eon- 10 consist of a cylindrical drum rotatable about its centric drums are combined With an sm f0!v axis. The stock is fed in at one end and flows Supplying or feeding pulp stock thereto, the feed-" along the drum to the other end over one or mechanism being adapted to increase th more annular rings Whieh extend inwardly o efiiciency of the several drums by decreasing the t drum The Stock fl i through the drum turbulence therein due to entering stock, and to 15 is held against the well f the drum y the afford a compact and convenient structure for trifugal "force of rotation. The capacity of a the apparatus as a wholeseparator of a given diameter, that is, the rate at more complete understanding of the which pulp can be passed through the drum and vention, reference may be had to the following 29 properly purified, is limited. when the Sepam description thereof and to the illustration thereof tor is first started up, the first pulp entering the on the drawing of drum forms a soft mat or lining within the drum Figure- 1 is eleYation of a centrifugal Over which flows the pulp. Stream This mat separator embodying the invention, aportion becombs. the fibers in the stream and catches and mg broken away to Show the interior parts in holds the dirt particles which are found therein. Section 25 The heavier dirt particles gradually work through 535?; g i' g g r of separator the drum toward the drum wall, while the mat g a ma er 1 Figure3 is a fragmentary section on a vertical itself tends to become gradually more compact. If increase of capacity is attempted by plane of the separator illustrated in Figure 1, on

a larger scale. This figure also indicates the creasing the speed of rotation above the optimum Speed the mat tends to pack rapidly and course of the pulp streams through the rotatable thus to diminish its capacity for catching and portlon of the mechamsm' The separator mechanism comprises a pluralholdmg parades from the pulp Streamity of coaxial drums mounted for rotation about Thus h ca 'pac1ty 4131.111)! be.1ncreased beyond their common axis. In the embodiment of the ina: certain point by an lhclease of of j vention illustrated onthe drawing, two drums I0 tion. The capacity of a separator of given diamand H are shown, the outer drum being m the B1191 however, he f doubled by h inner drum being ll. These drums are in general ing a Seco d drum W1thm the f t Sumclent of a cylindrical shape, the lower end of the drum 40 cleara ce belng provided between the Walls of i0 projectingashort distance below the lower end 40 the two drums for a stream of pulp to how along of the drum The drums are mounted as by a the wall o the Outel: A Second a is conical supporting member I3, on a vertical romtroduced i o e lnherdrum and flows along tatable shaft [4 which may be driven by a suitable the drum to the discharge end, where the streams motor 5 The conical member 3 has an from both drumsmay be discharged into a comardly extending flange is t th 10wer d 45 mon receiving c an into separate receivthereof on the. rim of which is mounted the drum ers. This increase of capacity requires no addiin, hi flange l arri th drum H t tional floor p that a Separator embodying latter being supported by a series of connecting the invention is especially advantageous where lugs l1. The drums may also be connected to 0 available floor space is limited. As the diameters each other and to the shaft at their upper ends 50 of the two drums preferably no not greatly differ, by radial tie-members as at 9. Pulp is supplied to a speed of rotation which is just suflicient for each of the drums at the lower end thereof, the the effective operation of the inner drum is suitpulp being pressed outwardly against the wall able for satisfactory operation of the outer drum of each drum by the centrifugal force of the rotaalso. More than two concentric drums or shells tlon of the drums. As additional pulp is supplied 55 to the lower ends of the drums, the pulp flows upwardly toward the top rim of the drums. The drums are each provided with one or more inwardly extending ribs I8 over which the stream of pulp must flow in its upward course. The upper portion l9 of each drum may be of somewhat greater diameter than the reminder of the drum, as shown on the drawing. At the upper end of this enlarged portion I9 is an inwardly extending flange 20 on the drum l0, and a similar flange 2| on the drum H. These flanges are arranged to form an annular pool of stock in each of the enlarged portions l9, into each one of which pools dips a skimming ring. The ring 22 which dips into the pool formed in the upper end of the drum l0 may conveniently be secured to the outer surface of the drum II. The inner skimming ring 23 which dips into the pool formed in the upper portion of the drum ll may be supported by radially extending arms 24. The streams of pulp in the pools must flow under the respective skimming rings so that all impurities of lesser specific gravity than the pulp are caught by the skimming rings and retained until the apparatus is stopped and washed out. The depth of the pool can be regulated within limits by adjusting the skimming rings so as to vary the narrow passage or clearance between the skimming ring and the sharp edge of the adjacent flange 20 or 2 I.

It is desirable to supply to each of the drums a separate stream of pulp stock. To this end, according to the invention, a pair of conical members 25, 26 may beprovided, these members extending downwardly, if desired, from short cylindrical members 21 and 28, respectively. The conical member 26 preferably extends down below the lower edge of the conical member 26, the lower edges of these members being arranged to be slightly above the lower ends of the respective drums. Thus stock supplied to the interior of the conical member 26 runs down the inner surface thereof and is discharged by centrifugal action from the lower rim to the inner surface of the drum Hi. In like manner stock supplied to the inner surface of the conical member 25 runs down and is discharged to the inner surface of the drum H. The members 25 and 26 are secured to the drums l0 and II and to the shaft [4 so that the drums and members rotate as a unit. Thus the stock which is fed into the upper ends of the members quickly acquires rotational motion around the common axis so that there is less disturbance of the pulp stream in the drums l0 and I l than where the incoming stream has not had previous rotational movement impressed thereon.

In order to supply suitable pulp stock to the rotating conical members, I may mount above the upper ends of the conical members, or rather the cylindrical elements 21 and 28 from which the conical members depend, a supply trough which is divided by guiding members into a pair of branch channels 36 and 3|. As shown in Figure 2, the delivery ends of these channels are bent around the axes of the drums in the direction of rotation. As each of the channels comes within its respective cylinder 21 or 28, the side of the channel 30 drops downwardly so as to extend below the lip of the cylinder 21, forming a guiding skirt as shown at 32 in Figure 3. In like manner the inner side of the channel 3| drops down to extend into the upper end of the cylinder 28, forming a guiding skirt as shown at 32. Pulp stock of suitable consistency is supplied through the channels 30 and 3|, the curved delivery portion of the channel serving to initiate the rotational movement of the stock, even before it comes in contact with the conical members 25 and 26. The rotation of these conical members greatly increases the rotative movement of the stock itself around the axis of rotation so that when the pulp stream reaches the lower ends of the conical members it is flung outwardly to the drums l0 and I I, but as it has acquired an annular speed of the drums there is little, if any, tangential flow within the drums, so that the disturbance of the pulp mass within the drums by the incoming stock is the minimum.

The provision of such stock feeding means for the drums offers several advantages. Since the conical members can be mounted within the innet drum, there is a considerable economy of space as the entire machine is not increased in external size by the addition of conical members within. Furthermore, a comparatively light construction is made possible since the upper ends of the drums can be secured by radially extending arms to the cylinder members 21, 28 which, in turn, may be secured to the supporting member [3 by spaced, radially extending links 9. The stream of pulp flowing over the sharp edges of the flanges 20 and 2| are given a combing action by-these edges which tends to break up fiber bunches and to smooth out the consistency of the pulp suspension. The streams issuing from the two drums may be caught in a common receptacle or channel 35 extending around the periphery of the casing 36 which contains the drums. As shown on the drawing the drums l0 and II and the casing 36 may be provided with suitable apertures in the bottom thereof to facilitate washing out the separator after use. The washing may be accomplished by simply playing a hose on the interior of the drums, the pulp mat being thereby washed down through the openings in the bottom of the drums in the casing.

I claim:

1. Centrifugal apparatus for purifying paper pulp, comprising a plurality of coaxial drums radially spaced and rotatable about their common axis, and means for supplying to each drum a stream of liquid to be purified, said supplying means including a plurality of conical members mounted coaxially within said drums and rotatable therewith, said conical members bein mounted with their larger ends radially inward of and adjacent to end portions of respective drums, means for feeding a stream of said liquid into each conical member at its smaller end, and means adjacent to the other ends of said drums for collecting liquid discharged therefrom.

2. Centrifugal apparatus for purifying paper pulp, comprising a plurality of coaxial drums rotatable about their common axis, means for supplying to each drum a stream of liquid to be purified, said supplying means including a plurality of conical members coaxial with said drums and a plurality of troughs having delivery portions circling about the common axis of said conical members, each said delivery portion having a lip extending downwardly into the upper end of a conical member, the lower ends of said conical members being in proximity to the lower ends of respective drums, and means adjacent to the upper ends of said drums for collecting liquid discharged therefrom.

3. Centrifugal apparatus for purifying paper pulp comprising a plurality of coaxial radially spaced drums rotatable about their common axis, the lower end of the outer drum extending below the lower end of the inner drum, means for rotating said drums, means for feeding stock to both said drums, said feeding means including a pair of conical members mounted within said drums for rotation therewith, the inner of said conical members having a lower edge on a level between that of the lower ends of the drums, the outer of said conical members having a lower edge a short distance above the level of the lower end of the inner drum, means for directing separate streams of stock into said conical members, and means for collecting the purified streams of stock issuing from the drums.

4. Centrifugal apparatus for purifying paper pulp, comprising a plurality of drums mounted one within another for rotation together about a common vertical axis, a collecting trough surrounding the upper edges of said drums to receive liquid discharged therefrom, and means for supplying separate streams of liquid to said drums at their lower end, said supply means including a plurality of conical members mounted within the innermost drum for rotation therewith, the smaller ends of said conical members being uppermost, the'larger ends of said conical members being in proximity to the lower ends of respective drums.

5. Centrifugal apparatus for purifying paper pulp, comprising a plurality of coaxial spaced drums, one within another rotatable on 'their common axis, means at one end of said. drums for collecting purified liquid discharged therefrom, and means for supplying each drum with a stream of liquid to be purified, said supply means including a plurality of coaxial nested conical members supported within said drums for rotation therewith, the smaller ends of said conical members being adjacent to the discharge end of the drums, the larger ends of the conical members being adjacent to the other end of said drums, each conical member being supported and arranged to supply from its lower edge a stream of liquid to a corresponding drum, and means for guiding previously separate streams of liquid into the small ends of the several conical members.

6. Centrifugal apparatus for purifying paper pulp, comprising a plurality of drums one within another and rotatable on a common vertical axis, and means for feeding separate streams of liquid to be purified into the lower ends of the several drums, said means including a plurality of conical hollow members coaxlally rotatable with said drums, the larger ends of said members being lowermost and respectively opposite the lower end portions of corresponding drums, a plurality of non-rotatable guiding members above said hollow members, each said guiding member havins a guiding skirt projecting into the upper end of a corresponding hollow member, and means for supplying separate streams of liquid to the several guiding members.

7. Centrifugal apparatus for purifying paper pulp, comprising a vertical rotatable shaft, a conical support member mounted on said shaft and rotatable therewith, said member having an outwardly projecting portion at its lower end, coaxial hollow drums supported by and rotatable with said outwardly projecting portion, and means for feeding separate streams of liquid to be purified to the several drums, said feeding means including a plurality of spaced nested conical members mounted on and coaxially rotatable with said support member, the lower ends of said feed members being respectively opposite the lower end portions of corresponding drums, and means for directing previously separate streams into the upper ends of the feed members.

8. Centrifugal apparatus for purifying paper pulp, comprising a vertical rotatable shaft, a support member secured to said shaft, said member extending outwardly and point of attachment to the shaft, said member also having a portion at its lower end projecting outwardly and provided with apertures of substantial area, an outer drum mounted on and rising upwardly from the rim of said outwardly projecting portion, an inner drum open at both ends supported by said outwardly projecting portion within the outer drum, and means for feeding separate streams of liquid to be purified into the several drums, said feeding means including coaxial hollow members mounted on and rotatable with said support member, said hollow members having their lower ends respectively opposite to the lower end portions of the several drums, means for directing previously separate streams of liquid into the upper ends of said hollow members, and means for collecting and uniting the separate streams discharged from the upper ends of the drums.

SVEN C. IINDBERG.

downwardly from the 

